Version 1.3 Sitemaps Broken

After upgrading the plugin to 1.3 I get this error on my sitemaps (not the index):

This page contains the following errors:
error on line 1 at column 1: Document is empty

http://www.cmj.com/page-sitemap.xml

They work with plugin version 1.2.5.

http://wordpress.org/extend/plugins/wordpress-seo/